The interest in superhydrophobic coatings have increased exponentially in the recentdecades due to their potential and versatility in their applications. The use forsuperhydrophobic surfaces range from water repellent fabric, to self cleaning surfacesand numerous applications in industry. In this project the durability of 6 differentsuperhydrophobic coatings have been examined. The durability was tested bydropping sand on the surfaces from a set hight of 10 cm and a flow of 40 g/min. Thesurfaces were mounted on a 45° angle. The surfaces were abraded for 30 seconds ata time and the static, receding, and advancing contact angles along with the roll-ofangle was measured. Five of the surfaces were built up with nano particles and onewas sand blasted and anodized to create a superhydrophobic structure. The surfacesthat withstood the most abrasion was the surface that had been calcined to improveadhesion and the surface that had been sand blasted and anodized. Measurementsshowed that the roll-off angle and the receding contact angle were the two bestindicators of the deterioration of a surface, while the static contact angle and theadvancing contact angle varied little with abrasion. The project was done at thecompany Technical Research Institute of Sweden (SP) at their chemistry, surfaces andmaterials department in Stockholm. All coatings and equipment was supplied by SP.

Various studies suggest tannins act as antioxidants, anticarcinogens, cardio-protectants, anti-inflammatory agents, and antimicrobials. However, more investigation is needed to examine the bioavailability of tannins. Tannins bind to salivary peptides by hydrophilic and hydrophobic mechanisms. Electrospray Ionization Mass Spectrometry (ESI-MS) has been used to assess both hydrophilic and hydrophobic components of protein complexes. ESI-MS could potentially be an effective tool for screening the bioavailability of tannins. Weaker binding tannins are predicted to be more highly absorbed by the body, and should therefore exhibit greater bioavailability. Rannulu and Cole have used ESI-MS to measure binding affinities of procyanidin tannin stereoisomers for salivary peptides in aqueous solution. The condensed tannins procyanidin B1, B2, B3, and B4 demonstrated significantly different binding affinities (binding strengths) for the Histatin 5 salivary peptide. The procyanidin-Histatin 5 binding mechanisms in the ESI-MS experiments by Rannulu and Cole were investigated using the FRED docking program combined with molecular dynamics optimization in the AMBER software suite. The simulations suggest residual liquid-phase binding interactions in procyanidin-Histatin 5 complexes are maintained in the gas phase under conditions resembling those in ESI-MS experiments, though the gas-phase interaction energies were enhanced. Increased hydrogen bonding and decreased π-π stacking interactions were also detected in gas versus liquid-phase procyanidin-Histatin 5 complexes. In addition, simulation results suggest multiple conformations of procyanidins bind Histatin 5 at several sites and procyanidin binding does not fix the Histatin 5 peptide backbone. The simulations agree with previous studies which indicate aromatic Histatin 5 residues are responsible for procyanidin-Histatin 5 binding and tannins can bind salivary peptides in multiple conformations. The effects of Hofmeister salts on complexation of an amphiphilic guest adamantane carboxylic acid to the hydrophobic surface of a deep-cavity cavitand have been investigated by Gibb et al. Adamantane-cavitand binding was found to be largely enthalpically driven, though adamantane binding in the presence of the salting-in anions perchlorate and thiocyanate was entropically driven. Gibb et al. also found that perchlorate-cavitand binding was enthalpically favorable, though entropically unfavorable. Potential-of-mean-force (PMF) calculations for perchlorate-cavitand and thiocyanate-cavitand complexation were performed using umbrella sampling with a modified version of the sander module from the Amber 9 software suite to further investigate the thermodynamic properties of Hofmeister-anion binding to the hydrophobic cavitand. The enthalpy for salting-in anion-cavitand complexation was calculated from the potential energy difference between the bound and unbound state (the potential energy of binding) along with the entropy. The binding entropy and enthalpy were also calculated using a finite difference approximation to the entropy. The enthalpy for perchlorate-cavitand complexation calculated from the binding energy and the finite difference approximation to the entropy was favorable with an unfavorable entropy. The binding enthalpy and entropy for thiocyanate-cavitand complexation calculated from the binding energy and finite difference approximation to the entropy were unfavorable and favorable, respectively, perhaps due to a classical hydrophobic effect. The orientation of the ligand, the number of water molecules displaced from the ligand and cavitand upon complexation, and the number of nearest-neighbor atom contacts between the ligand and the cavitand were also calculated. Additionally, the energetics of various interactions involved in salting-in anion-cavitand complexation including the anion-cavitand, anion-water, cavitand-water, and water-water interactions were assessed, though the data were inconclusive.

The durability of concrete structures is affected by a number of factors such as environmental exposure, electrochemical reactions, mechanical loading, impact damage and others. Of all of these, corrosion of the reinforcement is probably the main cause for the deterioration of steel reinforced concrete (RC) structures. Corrosion management is becoming increasingly necessary as a result of the growing number of ageing infrastructure assets (e.g. bridges, tunnels etc.) and the increased requirement for unplanned maintenance in order to keep these structures operational throughout their design life (and commonly, beyond). The main RC repair, refurbishment and rehabilitation approaches generally employed can be broadly categorised under a) conventional, b) surface treatments, c) electrochemical treatments and d) design solutions. The overarching aim of this research was to identify the key corrosion management techniques and undertake empirical investigations focused on full-scale RC structures to investigate their long-term performance. To achieve this, individual research packages were identified from the above broad five approaches for repair, replacement and rehabilitation. These were 1) Patch repairs and incipient anodes, 2) Impressed Current Cathodic Protection, 3) Galvanic Cathodic Protection and 4) Hydrophobic treatments. The selection of the above research packages was based on past and present use by the construction industry to repair, refurbish and rehabilitate RC structures. Their contributions may be broadly categorised as i) Investigations on how specific treatments and materials perform, ii) Investigations on the effectiveness of existing methods of measurements and developing alternatives, iii) Changes to the existing theory of corrosion initiation and arrest and iv) Changes to management framework strategies. The key findings from each research package can be summarised as follows: Macrocell activity appears to be a consequence rather than a cause of incipient anode formation in repaired concrete structures, as has previously been presented; ICCP has persistent protective effects even after interruption of the protective current; Discrete galvanic anodes installed in the parent concrete surrounding the patch repair are a feasible alternative to galvanic anodes embedded within the patch repairs of RC structures; Silanes may have a residual hydrophobic effect even after 20 years of service.

When confined within containers or conduits, drops and bubbles migrate to regions of minimum energy by the combined effects of surface tension, surface wetting, system geometry, and initial conditions. Such capillary phenomena are exploited for passive phase separation operations in micro-fluidic devices on earth and macro-fluidic devices aboard spacecraft. Our study focuses on the migration and ejection of large inertial-capillary drops confined between tilted planar hydrophobic substrates. In our experiments, the brief nearly weightless environment of a drop tower allows for the study of such capillary dominated behavior for up to 10 mL water drops with migration velocities up to 12 cm/s. We control ejection velocities as a function of drop volume, substrate tilt angle, initial confinement, and fluid properties. We then demonstrate how such geometries may be employed as passive no-moving-parts droplet generators for very large drop dynamics investigations. The method is ideal for hand-held non-oscillatory drop generation for fun, educational, and insightful astronaut demonstrations aboard the International Space Station.

Studies of submillimeter gels composed of covalently cross-linked poly(acrylic acid)-g-poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (Pluronic-PAA) networks are reviewed in light of potential applications of the microgels as drug carriers in oral delivery. The microgels are capable of volumetric transitions in response to environmental stimulae such as pH and temperature. It is shown that the type of Pluronic used in the microgel synthesis changes the structure of the resulting microgels, with the more hydrophobic Pluronic imparting porosity. Microgels based on Pluronic L92 (L92-PAA-EGDMA) possess higher ion-exchange capacity than microgels based on Pluronic F127 (F127-PAA-EGDMA), albeit the former are more hydrophobic. Analogously, more hydrophobic but heterogeneous L92-PAA-EGDMA exhibit superior capacity for equilibrium loading of hydrophobic drugs such as taxol, camptothecin and steroid hormones, as well as higher capacity for weakly basic drugs such as doxorubicin, mitomycin C, and mitoxantrone. / Singapore-MIT Alliance (SMA)

Doxorubicin (DOX) and Pluronic-PAA interaction was investigated using isothermal titration calorimetry (ITC). DOX/polymer interaction is governed primarily by electrostatic interaction. The uptake of DOX results in the formation of insoluble polymer/DOX complex. Addition of salt weakens the interaction of drug and polymer by charge shielding effect between positive ionized amino group on DOX and oppositely charged polymer chains. However high drug-loading capacity in high salt condition implied that self-association property of DOX also play a role in the drug loading process. / Singapore-MIT Alliance (SMA)

In recent years, the use of self-associating block copolymer based drug delivery systems have attracted increasing attention as nanoscopic carriers for the encapsulation and the controlled delivery of water insoluble drugs. Currently, most of the drug formulations proceed by trial and error method with no distinct method to predict the right combination of block copolymers and drugs to give all the desired functional properties. This is simply because such drug delivery systems involve complex intermolecular interactions and geometric fitting of molecules of different shapes. So, in the context of block copolymer design process, quantification and prediction of the interactions between potential block copolymers and the target drug are of great importance. Computer simulations that can predict the level and type of interactions encountered in drug/block copolymer pairs will enable researchers to make educated decisions on choosing a particular polymeric carrier for a given drug, avoiding time consuming and expensive trial and error based formulation experiments. In the present thesis, we reported the use of molecular dynamics (MD) simulation to predict the solubility of sets of hydrophobic drug molecules having different spatial distribution of hydrogen bond forming moieties in a series of micelle-forming PEO-b-PCL block copolymers with and without functionalized PCL blocks. The solubility predictions based on the MD results were then compared with those obtained from the solubility experiments and those obtained by the commonly used group contribution method (GCM). MD analysis techniques like radial distribution functions provided useful atomistic details to understand the molecular origin of miscibility and/or immiscibility observed between drugs and di-block copolymers. Based on the evidence of reported work, intermolecular specific interactions, intra-molecular interactions, local molecular packing, and stereochemistry of the hydrophobic block all play important roles in inducing miscibility between drugs and block copolymers. Additionally, not only the architecture of block copolymers but also the molecular characteristics of drug molecules, e.g., spatial distributions of hydrogen bond donors and acceptors on their molecules can affect the miscibility characteristics of binary mixtures. Depending on the groups present on drugs and block copolymers, any of the above factors can play vital role in the process of favouring encapsulation. The understanding of relative contributions of these interactions can help us to customize the performance of drug carriers by engineering the structure of block copolymers. / Chemical Engineering

Elemental sulphur (S0) is produced from processing bitumen from the oil sands region, Alberta. Long term storage of this S0 is under consideration. The objective of the current study was to determine the controls on water migration in variably saturated S0 blocks. Based on visual observations of S0 blocks, they were characterized as a hydrophobic fractured porous media. Thus, measurements of the hydraulic characteristics, including porosity (n) and hydraulic conductivity (K) of the matrix and the fractured media, were undertaken. These data were used to create characteristic relationships of unsaturated K (Kunsat) and volumetric moisture content (è) change with change in positive injection pressure (Ø).<p>Analyses showed that the mean total matrix n (nm) was 0.094 ± 0.035 (n = 280), the mean n available for water migration (na) was 0.065 ± 0.044 (n = 8) and the mean (geometric) K for the matrix was 2.0 x 10-6 ± 2.1 x 10-6 ms-1. In the case of vertical fractures, the aperture frequencies were measured to be 2.5, 10.0 and 21.0 m-1 for fractures with apertures > 1.4, 1.4 to 0.6 and < 0.6 mm respectively while the frequency of horizontal fractures, were measured to be 1.7 and 3.7 m-1 for with apertures > 1.4, and < 1.4 mm respectively. The fracture n (nf) was determined to be 0.0135. è Ø relationships were determined for both the fractured and non fractured media. From these plots, water entry values of 9 mm and 1 m were determined for the fracture pore space and the matrix pore space, respectively.<p>Simulations of packer tests resulted in a bulk saturated K (Kb) values ranging from 8.5 x 10-5 to 2 x 10-4 ms-1 above 9 m depth and 3 x 10-6 to 1.5 x 10-5 ms-1 below 9 m depth. Coupled Kunsat Ø and è Ø relationships were used to conceptually describe water migration in S0 blocks under different precipitation and mounding conditions. These plots also showed that the Kb is dominated by the fractures.

Elemental sulphur (S0) is produced from processing bitumen from the oil sands region, Alberta. Long term storage of this S0 is under consideration. The objective of the current study was to determine the controls on water migration in variably saturated S0 blocks. Based on visual observations of S0 blocks, they were characterized as a hydrophobic fractured porous media. Thus, measurements of the hydraulic characteristics, including porosity (n) and hydraulic conductivity (K) of the matrix and the fractured media, were undertaken. These data were used to create characteristic relationships of unsaturated K (Kunsat) and volumetric moisture content (è) change with change in positive injection pressure (Ø).<p>Analyses showed that the mean total matrix n (nm) was 0.094 ± 0.035 (n = 280), the mean n available for water migration (na) was 0.065 ± 0.044 (n = 8) and the mean (geometric) K for the matrix was 2.0 x 10-6 ± 2.1 x 10-6 ms-1. In the case of vertical fractures, the aperture frequencies were measured to be 2.5, 10.0 and 21.0 m-1 for fractures with apertures > 1.4, 1.4 to 0.6 and < 0.6 mm respectively while the frequency of horizontal fractures, were measured to be 1.7 and 3.7 m-1 for with apertures > 1.4, and < 1.4 mm respectively. The fracture n (nf) was determined to be 0.0135. è Ø relationships were determined for both the fractured and non fractured media. From these plots, water entry values of 9 mm and 1 m were determined for the fracture pore space and the matrix pore space, respectively.<p>Simulations of packer tests resulted in a bulk saturated K (Kb) values ranging from 8.5 x 10-5 to 2 x 10-4 ms-1 above 9 m depth and 3 x 10-6 to 1.5 x 10-5 ms-1 below 9 m depth. Coupled Kunsat Ø and è Ø relationships were used to conceptually describe water migration in S0 blocks under different precipitation and mounding conditions. These plots also showed that the Kb is dominated by the fractures.

Before studying to increase the catalyst utilization is one way to improve the performance of a fuel cell. But because it wastes a lot of time on making the hydrophobic pillared micro structures (HMPS) process. So this study aims to develop a fast and effective manufacturing method in order to increase the reaction surface area and catalyst utilization. The experiment has used the metal mesh stamping method to make the specific structure so as to increase the reaction surface area. The size of the metal mesh was the line path 35£gm, and the net square 70£gm*70£gm. The pressure was 300kg/cm2 and 500kg/cm2 that made the stamping structure in order to increase the reaction surface area. When the reaction surface area nearly increased 27 %, the performance also nearly increased 27 %; And when the reaction surface area nearly increased 36 %, the performance also nearly increased 36 %. So the increment of its performance nearly accorded with the increment of the reaction surface area. This method has saved a lot of time in the production process. Furthermore, the catalyst loading of cathode is halved in this experiment, the performance of fuel cell have no obviously decreased or reduced by half. As a result, the utilization of catalyst is raised.